SOURCE

const formsParams = (data) => {
    var arr = []
    for(var prop in data){
        arr.push(prop + "=" + data[prop])
    }
    return arr.join("&")
}
const ajax = async(options) => {
    let xhr = null;
    let { type, url, async = true, data } = options
    type = type.toUpperCase()
    let params = formsParams(data);
    //创建对象
    if(window.XMLHttpRequest){
        xhr = new XMLHttpRequest()
    } else {
        xhr = new ActiveXObject("Microsoft.XMLHTTP")
    }
    // 连接
    if(type == "GET"){
        xhr.open(type, url + "?" + params, async)
        xhr.send(null)
    } else if(type == "POST"){
        xhr.open(type, url, async)
        xhr.setRequestHeader("Content-Type","application/x-www-form-urlencoded")
        xhr.send(params)
    }
    xhr.onreadystatechange = function(){
        if(xhr.readyState == 4 && xhr.status == 200){
            options.success(xhr.responseText)
        }
    }
}
// https://www.maitanbang.com/
// ajax({
//     url : "https://www.maitanbang.com/api/hldh/index",
//     type : "GET",
//     data : {
//         key: 'KnDYcFP6qMoUBC19W4sdPqYkYZ',
//         coin: 'USD',
//         tocoin: 'CNY',
//         money: '10000'
//     },
//     success : function(data){
//         console.log(data)
//     }
// })